Convert the sample rate of your WAV files reliably, with Voxengo r8brain
Voxengo r8brain is a free and simple but demanding program that helps you to apply to a WAV recording the sample rate you need staying close to the initial quality.
Note that the program is also able to change bandwidth and bit depth, just in case you need that too.
If you are recording in a quality that is above CD quality, such as 48 kHz you may want to downgrade it to write a CD in the proper frequency of 44.1 kHZ.
Voxengo r8brain lets you also convert your music to a higher sample rate but of course inferior quality audio as a source cannot become better this way.